Process of refining textile materials containing natural and/or regenerated cellulosic fibers



United States Patent 3,396,050 PROCESS OF REFINING TEXTILE MATERIALS CONTAINING NATURAL AND/ OR REGENER- ATED CELLULOSIC FIBERS Heinz Enders, Stadtbergen-Augsburg, and Giinter Pusch, Leitershofen, Germany, assignors to Chemische Fabrik Pfersee G.m.b.H., Augsburg, Germany, a firm of Germany No Drawing. Filed Aug. 31, 1964, Ser. No. 393,422 Claims priority, appligrtionoGermany, Oct. 3, 1963,

7 Claims. c1.117 139.4

ABSTRACT OF THE DISCLOSURE This invention relates to a process of refining textile materials which contain natural cellulosic fibers, regenerated cellulosic fibers or a mixture of these two fibers.

It is known in prior art to treat textile materials containing natural and/or regenerated cellulosic fibers so that they should attain good dry and wet crease angles, as well as a good optical picture after washing (measured according to Monsanto wash-and-wear standards AATCC-88-l960). Prior art processes operate in at least two steps, whereby one step is concerned particularly with the dry crease angle which is obtained by cross-linking or condensation at raised temperatures, while a second step is particularly concerned with the wet crease angle obtained by cross-linking in a wet state.

It has been also suggested to obtain good dry crease angles as well as good wet crease angles by impregnating the textiles with an aqueous solution of a formaldehyde precondensate, drying them to a predetermined low residual moisture content and then applying to them a gaseous strongly acid catalyst, particularly gaseous hydrochloric acid.

The first-mentioned processes have the serious drawback that the textiles are subjected during one step to condensation at high temperatures and then are subjected to a wet storage process at room temperature. This requires an exceptionally long time for fitting out or finishing and thus the costs are increased due to diminished production. The last-mentioned process is very difficult to operate, since even small difierences in the moisture of the moving length of material result in 'a difierent absorption of the gaseous catalyst, and thus different results are obtained. Furthermore, it is necessary to have a special device for the treatment of textiles with the strongly aggressive gases.

An object of the present invention is to eliminate these drawbacks of prior art processes.

Other objects will become apparent in the course of the following specification.

In accordance with the present invention it was found that it is possible to provide textiles containing natural and/or regenerated cellulosic fibers with a very good dry and wet crease angle in a simple manner by applying to the textiles at most 45 (in relation to the dry weight of the textile material) of a bath containing a half acetal of formaldehyde with a 1 to 4-valent low 3,396,050 Patented Aug. 6, 1968 ice aliphatic alcohol, a strongly acid catalyst and at most 32% water, the textile material being allowed to remain for a long time at normal temperature, while avoiding as much as possible any loss in moisture, whereupon the treatment is completed by rinsing, neutralizing and drying.

Textiles which were thus treated have a very good wet and dry crease angle as well as a very good optical picture after washing. It is surprising that the treated textiles have a better abrasion resistance than those treated with a prior art two-step process resulting in the same finishing effects. At the same time a textile material treated in accordance with the present invention also has a most effective resistance against chlorine bleaches.

The term half acetal of formaldehyde with 1 to 4- valent low aliphatic alcohols is used herein the describe products obtained by known acidly catalyzed reactions of formaldehyde with corresponding alcohols in a ratio of 0.7 to 1.5 mol formaldehyde per equivalent hydroxyl groups. As alcohols may be used all commercially available alcohols with 1 to 6' carbon atoms. Preferably products are used which are derived from 1 and 2-valent alcohols with l to 3 carbon atoms.

As strongly acid catalysts are preferably used inorganic strong acids, such as hydrochloric acid or nitric acid. It is also possible to use, however, very strongly acid salts, such as aluminum trichloride or zirconium oxychloride.

The baths used in accordance with the present invention should containwith a water content of 5% to 32%65% to 93% of the half acetal and 1.5% to 6% of the strongly acid catalyst (calculated as free of water).

In case there is a disturbing formaldehyde smell of the bath, which cannot be completely avoided, for example, when there is no air suction device at the foulard, it may be advisable to replace up to two thirds of the total amount of the half acetal of formaldehyde with the low aliphatic alcohols, by methylol compounds of cyclic propylene or oxypropylene ureas. The effectsineluding chlorine resistance of the treated textileare essentially not diminished, so long as not more than two thirds of the half acetal are substituted.

If no high requirements are made concerning chlorine resistance, the above-mentioned methylol compounds of cyclic propylene or oxypropylene urea can be replaced by methylol compounds of cyclic ethylene urea, or ethylene 'diurea, or dioxyethylene urea. Similarly, it is also possible to use methylol compounds of urethanes of low aliphatic alcohols.

The temperature during the treatment of the textile material with the bath should amount to 10 C. to 33 C., while the duration of the treatment with the bath ranges between about 36 hours and about 4 hours, depending on the temperature.

The amounts of bath applied to the textile material should not exceed 45% thereof, in relation to the dry weight of the material, and should be preferably 20% to 37%. The application of these low amounts of the bath can be attained by processes known in the art, such as spraying, pressing on and using an application roller. A further and preferred method of attaining applications of such low bath pick ups consists in that length of the textile material which is impregnated in the bath of the present invention, is then rolled upon a support along with 1 to 4 dry untreated lengths of the same textile material and is then allowed to stand. This results in a completely uniform distribution of the bath received by one length of material upon all the other lengths which were rolled along with it.

The completion of the lengths of textile treated in accordance with the present invention is effected by rins- A white cotton poplin (90 cm. wide, 128 gr. per sq. m., 43 threads in the warp, 27 threads in the weft) was impregnated with a bath containing 80% of a half of formaldehyde and ethylene glycol (1 mol formaldehyde per equivalent hydroxyl groups), 3.5% hydrochloridic acid (of 100%) and 16.5% water, was then squeezed to a 65% bath content and was then firmly rolled upon a support jointly with a dry, untreated length of the same material; it was allowed to stand for hours at C. Thereupon the textile material was washed, neutralized with an aqueous soda solution, again rinsed and dried.

The treated textile material has a dry crease angle of 127 (average of warp and weft), a wet crease angle of 162 (average of warp and weft), a Monsanto-note of 5 and a loss of abrasion resistance of 16% in the acaccelorotor (3 min. at 3000 r.p.m.). The treated fabric is fully resistant against washing with chlorine, i.e. there is substantially no drop in tensile strength even under severest testing conditions (for example, Sanfor-plustest). Furthermore, the treated fabric, as compared to a fabric which was subjected to the normal resin treatment, has a very soft feel and a particularly good skin compatibility.

Example 2 A red colored cotton creton received by means of an application roller 30% (calculated on the basis of the air dry weight of the fabric) of a bath containing of a half acetal of formaldehyde with methyl alcohol (0.9 mol formaldehyde per mol alcohol), 36% dimethylol propylene urea, 4.5% hydrochloric acid (of 100%) and 19.5% water. The fabric was then rolled up, allowed to stand for 30 hours at 15 C. and then the treatment was completed in the manner described in Example 1. The dry crease angle amounted to 118 (average of warp and weft) and the wet crease angle amounted to 165 (average of warp and weft). The Monsanto-note was from 4 to 5.

Example 3 A spun-rayon twill was impregnated with a bath containing 40% of a half acetal of formaldehyde with isopropyl alcohol (1.3 mols formaldehyde per equivalent hydroxyl groups), of an aqueous solution of dimethylol glyoxal monourein and 15% of an aqueous 36% hydrochloric acid, was then squeezed to a bath content and was then firmly rolled upon a support jointly with a dry length of the same material; it was allowed to stand for 12 hours and then it was washed, neutralized, again rinsed and dried. The treated fabric has a very good wet and dry crease resistance without any noticeable diminution of abrasion resistance.

Example 4 A cotton poplin corresponding to that used in accordance with Example 1, was impregnated with a bath containing 90% of a half acetal of formaldehyde and ethyl alcohol (1 mol formaldehyde per equivalent hydroxyl groups), 5% concentrated nitric acid and 5% water; it

was squeezed to about 70% bath content and was then firmly rolled upon a support jointly with two additional lengths of the same material. After having been allowed to stand for 8 hours at 30 C., the fabric was washed, neutralized, again rinsed and then dried.

The treated fabric has a dry crease angle of 124 (average of warp and weft), a wet crease angle of (average of warp and weft), with a Monsanto-note of 5. The loss of abrasion resistance in accelerotor (3 min. at 3000 rpm.) amounts to 18%.

It is apparent that the examples described above have been given soley by way of illustration and not by way of limitation and that they are subject to many variations and modifications within the scope of the present invention. All such variations and modifications are to be included within the scope of the present invention.

What is claimed is:

1. A process of refining textile materials containing cellulosic fibers, comprising the steps of applying to a textile material at most 45% in relation to the dry weight of the textile material of a bath containing a half acetal of formaldehyde with a 1 to 4-valent low aliphatic alcohol having from 1 to 6 carbon atoms, a substance selected from the class consisting of a strong inorganic acid and very strongly acid reacting salt thereof, and less than 32% water, allowing said textile material to stand for a substantially long time at normal temperature and then rinsing, neutralizing and drying it.

2. A process in accordance with claim 1, wherein said bath contains from 5% to 32% water, 1.5% to 6% bydrochloric acid and 65% to 93% of the half acetal.

' 3. A process in accordance with claim 1, wherein the amount of the applied bath is 22% to 37%.

4. A process in accordance with claim 1, wherein said textile material is allowed to stand for a time period ranging between 4 to 36 hours.

5. A textile material treated in accordance with the process of claim 1.

6. A process of refining textile materials containing cellulosic fibers, comprising the steps of applying to a textile material at most 45% in relation to the dry weight of the textile material of a bath containing a half acetal of formaldehyde with a 1 to 4-valent low aliphatic alcohol having from 1 to 6 carbon atoms and a compound selected from the class consisting of the rnethylol compounds of cyclic alkylene ureas and oxyalkylene ureas, said compound amounting to at most the double by weight of said half acetal, a substance selected from the class consisting of a strong inorganic acid and very strongly acid reacting salt thereof, and less than 32% water, allowing said textile material to stand for a substantially long time at normal temperature and then rinsing, neutralizing and drying it.

7. A textile material treated in accordance with the process of claim 6.

References Cited UNITED STATES PATENTS 2,785,947 3/1957 Kress et al. 8-420 X 2,785,948 3/1957 Abrams 8116 3,015,584 1/1962 Reinhardt et al. 1l7l39.4 3,080,281 3/1963 Fisher et al. 167--49.5 3,215,489 11/1965 Kress l17-143 X WILLIAM D. MARTIN, Primary Examiner.

T. G. DAVIS, Assistant Examiner. 

